Turtle dig a 9*9

local x = 8
local y = 9
local z = 4

local fuel = turtle.getFuelLevel()
local roomSize = x * y * z
while fuel < roomSize do
  if not turtle.refuel(1) then
    print("Not enough fuel")
    return
  end
end

local direction = true
for i = 1, z do
  for j = 1, y do
    for k = 1, x do
      turtle.dig()
      while not turtle.forward() do turtle.dig() end
    end
    if j < y then
      if direction then
        turtle.turnRight()
        turtle.dig()
        while not turtle.forward() do turtle.dig() end
        turtle.turnRight()
        direction = false
      else
        turtle.turnLeft()
        turtle.dig()
        while not turtle.forward() do turtle.dig() end
        turtle.turnLeft()
        direction = true
      end
    end
  end
  if i < z then
    turtle.digUp()
    while not turtle.up() do turtle.digUp() end
    turtle.turnRight()
    turtle.turnRight()
  end
end